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The present study aims to elucidate the decomposition mechanism and gas evolution characteristics of a promising energy-rich carbamated microcrystalline cellulose nitrate (M3CN). The molecular structure and morphological characteristics of starting microcrystalline cellulose carbamate (MCCC) and its nitrated derivative were examined using FTIR and SEM techniques. Thermal analysis using TGA and DSC revealed distinct decomposition behaviors for MCCC and M3CN. MCCC exhibited endothermic decomposition linked to the degradation of the cellulosic structure. In contrast, an exothermic decomposition event was observed for M3CN, attributed to the cleavage of energetic groups within the nitrated cellulosic chains. Furthermore, the hyphenated TG-FTIR analysis confirmed that the primary gaseous products emitted during the pyrolysis of M3CN included NO, N2O, NO2, CO2, H2O, CH4, HCHO, HCN, and CHNO. The findings of this study enhance our understanding of the pyrolysis mechanism in cellulose-based energetic materials, providing a significant reference for forthcoming research and explorations in this field.

Development of green propellant is of importance for safer handling and higher cost effectiveness than conventional toxic hydrazine propellant. Among all green liquid propellant options, hydroxylammonium nitrate (HAN) offers better performance and exhibits lower toxicity than hydrazine. Extensive studies have been conducted on HAN decomposition using different techniques. Due to its ionic nature, HAN can be electrolyzed compared to hydrazine. Therefore, other than conventional thermal and catalytic decompositions, electrolytic decomposition of HAN is also possible. This review first discusses the decomposition mechanisms and summarizes the mechanisms involved in different decomposition techniques (thermal, catalytic, electrolytic and others). This review compares the relevant effects of various parameters in different decomposition techniques, with an overview on HAN-based propulsions systems developments systematically and comprehensively. Finally, this review concludes with future perspectives and challenges of different decomposition techniques. Herein, this work serves as a reference to understand the effects of various parameters under different HAN decomposition techniques, together with the limitations that hinders the application value of the decomposition techniques. • Hydroxylammonium nitrate (HAN) is safer to handle and less toxic than hydrazine. • Effects of different parameters on HAN decomposition are assessed. • Mechanisms for HAN decomposition are summarized and discussed. • Systematic and comprehensive overview of HAN-based propulsion systems developments. • Future perspectives of HAN decomposition technologies are prospected in this work. [ABSTRACT FROM AUTHOR]

The grain boundary diffusion process with Pr 60 Tb 10 Cu 30 alloy was used to improve the microstructure and coercivity of the hot-deformed Nd-Fe-B magnet. The crystalline intergranular phases consisting of (Pr,Nd) 5 Ga 3 , (Pr,Nd) 3 Co, PrCu and (Nd,Pr) 6 Fe 13 Ga were observed in the Pr 60 Tb 10 Cu 30 diffused magnet. Apparent (Nd,Tb) 2 Fe 14 B shell layer on the surface of Nd 2 Fe 14 B grains near the triple junctions of the magnet was observed after grain boundary diffusion. The formation of many non-ferromagnetic intergranular phases and Nd 2 Fe 14 B/(Nd,Tb) 2 Fe 14 B core-shell structure contributes to the significant increase of coercivity from 1.21 T to 2.7 T and the improvement of temperature coefficient of coercivity from −0.469%/℃ to −0.356%/℃. • The hot-deformed magnet with coercivity of 2.7 T is prepared by Pr 60 Tb 10 Cu 30 alloy diffusion. • The crystalline intergranular phases of (Pr,Nd) 5 Ga 3 , (Pr,Nd) 3 Co, PrCu and nano-sized (Nd,Pr) 6 Fe 13 Ga were observed in the diffused magnet. • Apparent (Nd,Tb) 2 Fe 14 B shell layer was formed near the triple junctions of the Pr-Tb-Cu diffused magnet. [ABSTRACT FROM AUTHOR]

This paper focus on the influence of oxygen on the partial discharge (PD) and decomposition characteristics of C 4 F 7 N/CO 2 /O 2 gas mixture as eco-friendly gas insulating medium. The PD characteristic parameters and phase resolved partial discharge (PRPD) patterns of C 4 F 7 N/CO 2 /O 2 gas mixture are, respectively, extracted and constructed. The influences of oxygen content and applied voltage on the PD and decomposition characteristics of C 4 F 7 N/CO 2 /O 2 gas mixture are investigated based on gas chromatography-mass spectrometry (GC-MS). We find that the addition of 2-4% O 2 to C 4 F 7 N/CO 2 gas mixture can significantly inhibit the negative half-cycle PDs and the generation of most by-products (CF 4 , C 2 F 6 , C 3 F 6 , CO, C 2 F 6 O 3 , CF 3 CN, C 2 F 5 CN, C 2 N 2). With the oxygen content higher than 6%, the accumulation discharge magnitude and discharge repetition rates of C 4 F 7 N/CO 2 /O 2 gas mixture increase sharply, accompanying the intensification of decomposition and deterioration of insulation strength. There is a positive correlation between the mean discharge magnitude and gas mixture decomposition intensity. To avoid the serious impact of PD fault on gas insulated equipment (GIE), the optimal oxygen addition in C 4 F 7 N/CO 2 /O 2 gas mixture should not exceed 6%. [ABSTRACT FROM AUTHOR]

Hexanitrostilbene plays an important role in aerospace and space technology because of its excellent chemical stability. However, carbon deposition during the explosion seriously affects its detonation performance. A newly parameterized reactive force field was used to simulate the decomposition behavior of nanometer aluminized hexanitrostilbene. Aluminum nanoparticles and the corresponding surface oxidized ones were mixtured with the hexanitrostilbene to build nanometer aluminized composites. The simulation results show that aluminum nanoparticles lead to an earlier decomposition of hexanitrostilbene in a new way. Aluminum nanoparticles follow diffusion oxidation theory in the heating. At high temperatures, Aluminum nanoparticle quickly splits and exposes active aluminum to participate in the reaction. The presence of oxide layer in surface oxidized aluminum nanoparticle is less attractive to oxygen, carbon and nitrogen atoms, and surface oxidized aluminum nanoparticle is difficult to split into small particles during ignition and detonation. Aluminum nanoparticles prevent the formation of larger carbon clusters and cause hydrogen and oxygen atoms escape from carbon clusters. This is the main reason for the increasing detonation pressure and energy outputs of nanometer aluminized Hexanitrostilbene. Adiabatic simulation shows that nanometer aluminized hexanitrostilbene decomposes faster and releases more energy than pure hexanitrostilbene. This work provides insights for the application of aluminized hexanitrostilbene composites in aerospace. • ReaxFF-lg is used to simulate the thermal decomposition of nano-aluminized HNS. • Al nanoparticles lead to an earlier decomposition of HNS in a new pathway. • Evolution behavior of nano-Al during heating follows diffusion oxidation theory. • Nano-Al prevents the agglomeration of carbon. • Gas production and energy outputs of nano-aluminized HNS are greatly improved. [ABSTRACT FROM AUTHOR]

• A new modified double-base propellant was successfully elaborated and characterized. • The presence of co-crystals has increased the density of the resulted propellant. • The studied energetic composite shows a satisfactory specific impulse of 247.1 s. • The designed propellant displays improved heat release of 3010.2 J/g. • Kinetic results demonstrate the increased reactivity of the developed propellant. This work aims to investigate the characteristics of a modified double-base propellant based on hydrazine 3-nitro-1,2,4-triazol-5-one and ammonium nitrate (HNTO/AN), nitrocellulose (NC), and diethylene glycol dinitrate (DEGDN), for which the optimal formulation was selected based on theoretical performance calculations. Structural and morphological results demonstrated that HNTO/AN co-crystals were homogenously distributed within the NC-DEGDN matrix without discernible alterations in the chemical structure. Furthermore, thermal analyses provided substantial evidence of the mutual thermal decomposition effect between HNTO/AN and NC-DEGDN. Indeed, thermal findings highlighted that the addition of HNTO/AN accelerated the thermolysis of NC-DEGDN propellant and significantly increased its heat release by approximately 1042.8 J/g. Additionally, a notable decrease in the activation energy was also observed, revealing the catalytic influence of HNTO/AN microparticles on the thermolysis of NC/DEGDN propellant. [Display omitted] [ABSTRACT FROM AUTHOR]

The organogermane GeH2Cp*2 (1) was synthesized by the reaction of GeCl2Cp*2 (A) with LiAlH4 in quantitative yield, whereas the synthesis of the previously reported compounds SiCl2Cp*2 (B), SnCl2Cp*2 (C), SiClHCp*2 (D) and SiH2Cp*2 (E) followed established routes. The molecular structures of the Cp*M(IV) derivatives 1, B, D and E are reported. In addition, compound 1 was characterized by spectroscopic methods such as 1H and 13C{1H} NMR spectroscopy, ATR-FTIR spectroscopy and EI-mass spectrometry. The thermal behavior of the germanes 1 and A was investigated by thermogravimetric analysis (TGA, DSC) and PXRD. The decomposition of compounds A and 1 starts at 270°C (A) and 200°C (1), respectively. The formation of crystalline Ge upon heating these compounds in sealed quartz glass capillaries was observed at 270°C (A) and 500°C (1).

Scanning electron microscopy(SEM)， transmission electron microscopy(TEM)， X-ray diffraction(XRD) and tensile tests were used to investigate decomposition behaviors of the retained austenite(RA) in hot rolled TRIP steels with lowSi and some Al elements during isothermal treatments. The results showthat during different isothermal temperature， the RA can decompose into ferrite and carbides gradually with the isothermal time. When the isothermal temperature increases， the time required for the RA decomposition decreases. At different isothermal temperature， the variation tendency of tensile strength， total elongation and strength ductility balance of the tested steel decreases with the isothermal time. With different isothermal treatments， the variation of the volume fraction of the RA tends to be decreased， while the carbon content has little effect. [ABSTRACT FROM AUTHOR]

• A promising chitosan-based energetic polysaccharide was synthesized through nitration process. • Nitrochitosan (NCS) greater nitrogen content and heat release than the common nitrocellulose. • Hyphenated thermogravimetry-infrared spectroscopy tool was used to identify the evolved gaseous. • Thermal decomposition mechanism of NCS was elucidated for the first time. • NCS showed the great potential to be applied in future energetic formulations. High-substitute nitrochitosan (NCS) was synthesized via the esterification of chitosan, and its characteristics were deeply investigated. The chemical functionalities and morphological features of the starting chitosan and its nitrated derivative were scrutinized by FTIR and SEM analyses. Thermal characterizations by TGA and DSC showed that NCS has two consecutive exothermic processes, involving the thermolysis of explosophoric functional groups accompanied by the thermo-oxidative degradation of the polymeric framework. In addition, hyphenated TGA-FTIR characterization highlighted that the main evolved products during NCS decomposition are NO, NO 2 , CO 2 , H 2 O, CH 4 , HCN, and CH 2 O. [ABSTRACT FROM AUTHOR]

Solid ion conductors are moved into the focus of energy‐related science as thermoelectric materials due to their high ion mobility and their ability to scatter phonons. A second interesting phenomenon of some solid ion (and electron) conductors is the possibility to perform a pnp switch of their semiconductor mechanism during a structural phase transition. During our search for new pnp switching systems we examined trimorphic, argyrodite‐type Cu7PSe6 as a potential candidate. Recently, this phase was reported to be a reasonable thermoelectric material, which combines to the statements given above. The ion mobility in a solid can be a beauty or a beast concerning the stability of the compound during thermoelectric operation. In this article we report on the electric conductivity and thermopower evolution of Cu7PSe6, a trimorphic, mixed ion and electron conductor. Slightly above room temperature this compound undergoes an order‐disorder phase transition where Cu tends to become almost liquid in the framework of the anions. Intending to verify the possibility of a pnp switch during this order‐disorder transition we started a systematic evaluation of the (thermo)electrochemical behavior of this phase. Unfortunately, this material does not perform a pnp switch but it also shows a well‐defined decomposition behavior upon thermoelectric cycling. In this contribution we report on the change and evolution of properties during the characterization process, which manifests in a continuous variation of the total electric conductivity and thermopower upon thermoelectric cycling. This study reflects the importance and need of stability studies of solid ion conductors in the entire range of thermoelectric application especially if order‐disorder phase transitions and high ion mobilities are present which can cause significant mass transport and phase separation within the sample. [ABSTRACT FROM AUTHOR]

To improve the thermal performance and mechanical properties of nitramine propellant, varied proportions of GAP-ETPE/NC were applied as binders. The thermal behavior of propellants was investigated by using differential scanning calorimetry (DSC), the thermal stability of the propellants was studied by methyl violet experiment and vacuum stability test, and the mechanical properties were also examined. It was found that the DSC curve of GAP-ETPE shows a single exothermic peak at around 250 °C, and TG-DTG curves of GAP-ETPE exhibit two major steps of mass loss. GAP-ETPE has a good compatibility with nitrocellulose, and there is no interaction between GAP-ETPE and RDX in solid phrase. When increasing the proportion of GAP-ETPE content in the binder system, the decomposition peak of nitrocellulose disappears gradually and the peak temperature of main decomposition increases. Meanwhile, activation energy and frequency factor calculated by Kissinger and FWO methods using non-isothermal thermoanalytical data all increase slightly. And the thermal stability of propellant gets improved greatly when GAP-ETPE is introduced into the binder system. When the proportion of GAP-ETPE/NC is 1:1 and 1:2 in the binder system, the mechanical properties of nitramine propellant are relatively excellent. [ABSTRACT FROM AUTHOR]

Better understanding the decomposition and dissolution behaviors of limestone under steelmaking condition is essential to evaluate the possibility of directly using limestone instead of lime in converter. In this paper, the decomposition behavior of limestone in early converter slag including the decomposition kinetics and microstructure of the produced lime layer were studied, and the effects of slag temperature and stirring speed introduced to the slag bath were examined. Kinetic analysis based both on shrinking core model and dimensionless chemical-heat transfer number ( N CH ) showed that the limestone decomposition at 1300–1400 °C was a mixed control of chemical reaction and heat conduction through the lime layer. Slag temperature has a significant influence on the decomposition process while the stirring speed plays a minor role when a critical stirring intensity is reached. The obtained effective thermal conductivity varied from 0.21 to 2.51 W m − 1 K − 1 and the chemical reaction rate constant ranged between 7.9 × 10 − 4 and 6.3 × 10 − 3 m s − 1 . The produced lime layer has less grain size and apparent porosity than the calcined one. Besides, smaller limestone particle and more heat supply to the converter bath are recommended to accelerate the limestone decomposition in early converter slag. [ABSTRACT FROM AUTHOR]

The organogermane GeH2Cp*2 (1) was synthesized by the reaction of GeCl2Cp*2 (A) with LiAlH4 in quantitative yield, whereas the synthesis of the previously reported compounds SiCl2Cp*2 (B), SnCl2Cp*2 (C), SiCl- HCp*2 (D) and SiH2Cp*2 (E) followed established routes. The molecular structures of the Cp*M(IV) derivatives 1, B, D and E are reported. In addition, compound 1 was characterized by spectroscopic methods such as ¹H and 13C{¹H} NMR spectroscopy, ATR-FTIR spectroscopy and EI-mass spectrometry. The thermal behavior of the germanes 1 and A was investigated by thermogravimetric analysis (TGA, DSC) and PXRD. The decomposition of compounds A and 1 starts at 270°C (A) and 200°C (1), respectively. The formation of crystalline Ge upon heating these compounds in sealed quartz glass capillaries was observed at 270°C (A) and 500°C (1). [ABSTRACT FROM AUTHOR]

The organogermane GeH2Cp*2 (1) was synthesized by the reaction of GeCl2Cp*2 (A) with LiAlH4 in quantitative yield, whereas the synthesis of the previously reported compounds SiCl2Cp*2 (B), SnCl2Cp*2 (C), SiCl- HCp*2 (D) and SiH2Cp*2 (E) followed established routes. The molecular structures of the Cp*M(IV) derivatives 1, B, D and E are reported. In addition, compound 1 was characterized by spectroscopic methods such as ¹H and 13C{¹H} NMR spectroscopy, ATR-FTIR spectroscopy and EI-mass spectrometry. The thermal behavior of the germanes 1 and A was investigated by thermogravimetric analysis (TGA, DSC) and PXRD. The decomposition of compounds A and 1 starts at 270°C (A) and 200°C (1), respectively. The formation of crystalline Ge upon heating these compounds in sealed quartz glass capillaries was observed at 270°C (A) and 500°C (1). [ABSTRACT FROM AUTHOR]

Ion-exchange chromatographic analysis of peroxynitric acid (O 2 NOOH) was performed by combining an acidic eluate with an UV–vis detector and immersing the separation column in an ice-water bath. The decomposition behavior of peroxynitric acid in the solution was also studied using this system. The fraction for the peroxynitric acid peak was collected. Ion-exchange chromatographic analysis of this fraction, after standing at room temperature for 24 h, showed that the decomposition products were mainly nitrate ions with a very small amount of nitrous acid. The peroxynitric acid peak area correlated perfectly with the total amount of decomposition products. The ion-exchange chromatographic isolation allowed us to evaluate the molar extinction coefficient of peroxynitric acid precisely in a wider wavelength range than previous reports. The value decreases monotonically from 1729 ± 26 M −1 cm −1 at 200 nm to 12.0 ± 0.5 M −1 cm −1 at 290 nm. [ABSTRACT FROM AUTHOR]

This paper aims to provide fundamental knowledge to prepare rutile TiO 2 from titanium slag (71.66% of TiO 2 , 7.70% of Total Fe) with the assistance of sodium carbonate roasting and microwave heating. The decomposition behaviors of the as-received titanium slag were investigated with experimental comparing groups, namely one group using conventional heating technique and another group using microwave heating technique, respectively. To understand the fundamental knowledge on the decomposition behaviour of titanium slag, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and laser particle size analyzer (LPS) were responsible for the evaluating of the products. Additionally, the influence of sodium carbonate on the phase transformation process was studied. The results indicate that the insoluble Na 2 Fe 2 Ti 6 O 16 phase was detected in the conventional roasted product with a low Na 2 CO 3 /slag ratio, while this phenomenon was absent in the microwave roasted product. With the increasing amounts of Na 2 CO 3 , the particles of the final produced TiO 2 have a transformation from irregular shape to rod-like shape. Compared to the products produced by conventional heating techniques, the rod size of the products using the microwave heating technique is more refined. The noticed structure indicated that the microwave heating technique improves the crystallinity growth at a lower Na 2 CO 3 /slag ratio. The FT-IR results revealed that products' adsorption ability was enhanced with an increase in Na 2 CO 3 /slag ratio and the application of microwave heating techniques. The LPS exhibited that the increase of Na 2 CO 3 /slag ratio restrained the particle size of rutile TiO 2 , which was more evident for the microwave roasted product. [Display omitted] • Microwaves as the energy source to enhance the reduction of titanium slag. • Heating transfer mechanisms between microwave and conventional heat were obtained. • Mineral reconstruction and regulated method of titanium slag were characterized. • Rutile TiO 2 has been synthesized successfully. [ABSTRACT FROM AUTHOR]

Microcrystalline cellulose (avicel) is treated in hot-compressed aprotic solvents, sulfolane and 1,4-dioxane, using a batch-type reaction system with a molten tin bath in a range from 290 to 390°C. The corresponding densities of the solvent are 0.25–1.26 g/cm3 and 0.21–1.03 g/cm3 for sulfolane and 1,4-dioxane, respectively. As a result, in both solvents, more than 90% of cellulose is found to be decomposed to the solvent-soluble portion in which levoglucosan is the main component with the highest yield of about 35% on original cellulose basis. The decomposition rate to levoglucosan is, however, faster in sulfolane than in 1,4-dioxane, while levoglucosan is more stable in 1,4-dioxane. In addition, its yield is found to be solvent-density dependent to be highest around 0.4–0.5 g/cm3 for both solvents. To elucidate these decomposition behaviors, the results obtained in this study with aprotic solvents are compared with protic solvents such as water and methanol in previous works. [ABSTRACT FROM AUTHOR]